Reversing blower kiln



Apr. 17, W23. KASLM? H. D. TIEMANN ET AL REVERS ING BLOWER K ILN Filed Jan 24, 1921 OOOOO(\ Ro/f The/en Harry D 772m 0/7 IN VEN TORS ATTORNEY ltl lll

l otented Apr, 117, ltlhdl tartan EEVEESHTG Bhtl'WlllSl htllhll.

Application tiled January as, wal serial the. traces.

(HLED UNDER THE ACT 0E MARCH ll, 1883, 22 TdT.-E., ilth.)

To all whom it may concern Be it known that We, HARRY l). TIEMANN and hour .Tnnrnn, citizens of the United States of America, and employees of the Department of Agriculture, residing in Madison, Wsconsin, whose post-office address is Madison, Wisconsin, have jointly invented a new and Improved ever-sing Blower Kiln.

This applicationis made under the act of March 3, 1883, chapter 143 (22 Stat, 625), and the invention herein described and claid ma be used by the Government of the liiallted tates, its ofiicers and employees, and by any person inthe- United States without payment to us of any royalty there- Ell till

@ur invention consists in an improvement in the design of blower or forced circulation kilns or chambers for drying and conditioning lumber or similar material; however, its use is not limited to wood erclusivel lit consists of peculiar means for pro ucing unique internal circulation or the air and vapor combined with the production and regulation of-heat and humidity within a suitable chamber in which the material to 'be dried or conditioned is stacked.

The apparatus is shown in l i are "l. which represents a cross-sectional e evation of the kiln. I 1

'ln the-drawings the housing has been broken away to show the fans or blowers.

e principal features which we claim as novel and an improvement over existing kilns arez-A peculiar arrangement of the fans or blowers within the kiln so that'the movement of the air and vapor through the pile of lumber is uniform, and reversible in directiop during the drying. This causes drying or conditioning to take place uniformly in all portions of the pile and eliminates the lag which occurs in other positive circulation kilns and in ventilated 'kilns, between the two sides of the pile. This permits not only more uniform but also quicker drying of the pile as a whole. 'lhe lacing of one or more series of blowers or runs within the min, each series consisting of a number of blowers or fans spaced at regular intervals lengthwise of the kiln, and

within thev dryin'g'chamber, thus assuring a more positive and ual I 9 throughout the len t the an n is ohat each side.

air movement tainable with distributing ducts, combined with the attachment of each of the blowers of a series upon a single line shalt, propelled preferably by a motorat one point on the shaft. One series 0 blowers may be placed on either side, not to be used jointly, but alternately for reversing the circulation. ln

wide kilns, a multiplicity of shafts may be ufiel, a row of blowers mounted on each s a t.

An well-known means of heating the air may e used in conjunct'on with the fans or blowers When steam pipes are used these may be concentrated towards the center or axis of the kiln, beneath the platform floor, and directly in the air current from either series of blowers, and preferably consist of return bend coils placed edgewise or diagonally, each coil having separate valves scribed but may make use of any other suitable means for accomplishing the same purpose. Fresh air inlets are provided for each blower with suitable dampers, and outlets near the top ofthe walls, also with suitable dampers. These inlets and outlets are for the sole purpose of reducing the humidity and usually have but little bearing on'the circulaton, the circulation being mainly internal of the drying chamber.

The platform upon which the lumber pile rests is plunked over solid above the steam coils but may have narrow openings for air placed at each side of the platform to break up vortex action. and deflect some of the air through the lower layers of lumber. The running boards and deflectors M, are designed to act in a similar manner. A curtain or curtains J may be dropped from "the root to the pile to prevent air from flowing over and around the pile, and'also to cause some air to pass downwards time 1 h the top of the pile. Adjustable hinged a. doctors or dampers may be placed along'the upper corners of the lriln toeeuse air to Vertical bafies l-l may be ill? enter the upper layers from the side of the pile in a horizontal direction.

. The blowers or fans are placed atv ap proximately equal intervals of a few feet apart throughout the length of the kiln and may be designed to deliver approximately 200 cubic feet of air per minute for each foot length of kiln at a low pressure approximating ounce-water pressure.

The lumber is preferably fiat piled lengthwise either on trucks running on rails or di rectly upon the kiln platform. Horizontal spaces may be left between adjacent boards and the spaces in consecutive layers should be staggered.

While the specification describes, and the drawing illustrates, a specific form of flat piled lumber through which the air current passes first in one direction and other, we do not wish to limit the scope of the claim to this particular form, since the improvement is equally applicable to other well-known forms of piling, such as single piles with central chimneys, in which the main air current passes inward toward, or outward from these chimneys; double piling with chimneys in each pile, current in the space between the piles moves in the same general direction as between the piles and the wall; inclined piling; vertical piling; and other forms.

Referring to the drawing which represents a cross-sectional elevation of the drying chamber, the longitudinal axis being perpendicular to the plane'of the drawing :-K designates the side walls of the drying chamber and L the loadof lumber to be dried. The blowers or fans B-are located at regular intervals upon the line shafts C. A indicates suitable housings for the fans or blowers, arranged so as to draw air downward from the spaces between the lumber and the walls and discharge it beneath the lumber over the heating coils. This is in order that the direction of the air circulation will be reversed when one series stopped and the other series started. It is obvious that the amount and velocity of the then in the and in which air near the base of of the blowers is air motion may be controlled at will by controlling the speed of the fans or blowers. D

represents dampers in the housings of the fans or blowers communicating with fresh:

air inlets. E designates the heating coils previously described, F the steam jets for humidifying the air. 1 is the platform supporting the lumber; H the baflles for overcoming vortex motion; 0 the moist air outlets, which although shown near the roof, may be placed at any convenient location. J indicates canvas curtains to prevent the air from short circuiting the pile of lumber. M are running boards along the sides of the kiln, which act also as deflectors. In the drawing R represents electric motors adapted to drive the line shafts C by means of pulleys Q and N and belts P. Switches S serve to start and stop the motors. The motors are intended to be operated alternately, each period of operation being several hours or more. Stopping one motor and starting the other has the effect of reversing the direction of the air movement through the lumber.

Having fully described the construction and operation, we claim as original .In a dry kiln, two series of blowers placed the kiln and respectively at opposite sides thereof, two shafts on which said series are respectively mounted for ro-' tation, discharge ducts for said blowers, the

ducts of each series respectivelg being adapted to discharge the drying me ium upwardly against the opposite side of the kiln, and means for rotating said shafts whereby they may be driven alternately to cause a reversal of the circulation of the drying medium in said kiln.

In testimony whereof we afiix our signatures in the presence of two subscribing witnesses.

HARRY D. TIEMANN. ROLF THELEN.

Witnesses:

ARTHUR UPSON,

O. M. TATLER. 

